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United States Patent Application	20090223975
Kind Code	A1
McCallister; Glenn Miller	September 10, 2009

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Claims

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1. A liquid-holding tank for mounting on the frame of a vehicle, the tank comprising:an elongate tank body having curved side walls coupled to and disposed above a generally rectangular frame, the elongate tank body defining an interior chamber;the frame having generally vertical side walls extending from a generally planar tank floor, the generally vertical side walls coupled to the curved side walls, the frame adapted to directly support the tank on the vehicle frame, the frame further adapted to be in fluid communication with the chamber and receive the liquid, thereby lowering a vertical center of gravity of the tank;front and rear vessel heads coupled to the curved side walls and frame;a lid coupled to the curved side walls and the vessel heads;at least one longitudinal baffle coupled longitudinally inside the chamber; andat least one transverse baffle coupled transversely inside the chamber.

2. The liquid-holding tank of claim 1, further comprising a venting system for continuously venting the tank, the venting system comprising:a generally vertical vent pipe having upper and lower ends, the upper end penetrating through the lid and the lower end extending into the frame; anda generally horizontal vent trough coupled to the lower end of the vertical vent pipe, the vent trough being formed in the frame of the tank and extending toward a drain.

3. The liquid-holding tank of claim 1, wherein the at least one transverse baffle divides the chamber into lateral sections, the at least one transverse baffle having lower passages which permit moderated longitudinal movement of the liquid in the chamber.

4. The liquid-holding tank of claim 3, wherein the at least one transverse baffle comprises a peripheral flange extending at least partially around the at least one transverse baffle, wherein the peripheral flange is coupled to an interior surface of the frame to provide structural support to the frame.

5. The liquid-holding tank of claim 3, wherein the at least one transverse baffle comprises:a transverse baffle ring having an outer edge having a profile;a metal strap formed to match a lower portion of the outer edge profile, the metal strap being coupled to the outer edge along the lower portion, thereby forming a flanged ring coupled to an interior surface of the frame to provide structural support to the frame; anda transverse baffle plate coupled to the transverse baffle ring;

6. The liquid-holding tank of claim 3, wherein the at least one transverse baffle comprises at least one service access port and a corresponding cover for access between the lateral sections of the chamber.

7. The liquid-holding tank of claim 6, wherein the cover is cut from the at least one transverse baffle along a generally circular profile having at least two radially projecting tabs, wherein the radially projecting tabs are adapted to attach the cover to the service access port forming at least two voids left from removal of the tabs.

8. The liquid-holding tank of claim 1, wherein the at least one longitudinal baffle divides the chamber into longitudinal sections having moderated communication of the liquid therebetween, the at least one longitudinal baffle comprising segmented panels, the segmented panels being coupled between adjacent transverse baffles.

9. The liquid-holding tank of claim 1, wherein the at least one longitudinal baffle comprises a first plurality of panels coupled between adjacent transverse baffles, a second plurality of panels coupled between a rear transverse baffle and the rear vessel head, a first single panel coupled between the front vessel head and a vertical vent pipe, and a second single panel coupled between the vertical vent pipe and a front transverse baffle.

10. The liquid-holding tank of claim 9, wherein each of the transverse baffles comprise one or more vertical brackets with horizontally slotted holes adapted to receive fasteners securing the first and second plurality of panels and the second single panel to the vertical brackets.

11. The liquid-holding tank of claim 1 wherein the lid comprises a removable tank cover removably coupled to the curved side walls, the removable tank cover adapted to provide overhead access to the chamber.

12. A liquid-holding tank for mounting on the frame of a vehicle comprising:an elongate tank body having curved side walls coupled to front and rear heads, the tank body generally defining an upper liquid containment area;a closed-bottom tank frame coupled to the curved side walls and further coupled to and extending between the front and rear heads, the tank frame extending downwards, and generally defining a lower liquid containment area which is fully open to the upper containment area, the upper and lower containment areas forming a total containment area, the lower containment area operable to lower a vertical center of gravity of the total containment area, the tank frame comprising an integral structural support, the tank frame directly contacting the vehicle frame;a baffle system arranged to compartmentalize the total containment area, the baffle system comprising a plurality of longitudinal and transverse baffles; anda top coupled to the elongate body.

13. The liquid-holding tank of claim 12, wherein the top has longitudinal edges, the top comprising at least two upwardly projecting vertical ribs coupled to and generally extending along the longitudinal edges of the top.

14. The liquid-holding tank of claim 13, wherein the top further comprises at least one end panel coupled between the vertical ribs.

15. The liquid-holding tank of claim 13, wherein the top and vertical ribs are configured to form a storage area.

16. The liquid-holding tank of claim 13, wherein the top further comprises an access port and a vertical vent hole, both located between the vertical ribs, the vertical ribs providing roll-over protection for the access port and the vertical vent hole.

17. The liquid-holding tank of claim 13, wherein the vertical ribs each comprise a conduit space.

18. The liquid-holding tank of claim 17, further comprising at least one vessel head channel coupled to the front head, the vessel head channel being in open communication with at least one of the conduit spaces, and the vessel head channel adapted to structurally support the front head.

19. A liquid-holding tank for mounting on the frame of a vehicle, the tank comprising:an elongate tank body; anda tank frame coupled to the elongate tank body and extending downwardly therefrom, the tank frame and the elongate tank body forming a reservoir, the tank frame adapted to rest directly on the vehicle frame.

20. The liquid-holding tank of claim 19, further comprising a plurality of gusset braces coupled externally to both the tank frame and the tank body to provide support for the tank body.

21. The liquid-holding tank of claim 19, wherein the tank frame comprises at least one internal transverse structural support.

22. The liquid-holding tank of claim 19, wherein the tank frame is adapted to simultaneously support the tank body and hold the liquid.

23. The liquid-holding tank of claim 19, wherein the tank frame is adapted to be bottom-supported directly by the vehicle frame without any intervening support structure between the vehicle frame and the tank frame.

24. The liquid-holding tank of claim 19, wherein the tank frame bears directly on the vehicle frame, and wherein sliding and separation between the tank frame and the vehicle frame are substantially prevented by at least one pair of side-attached mounts, each side-attached mount coupled across corresponding outer surfaces of the tank frame and the vehicle frame.

25. The liquid-holding tank of claim 24, wherein the side-attached mounts comprise rigid mounts for rearward attachment and spring-dampened mounts for forward attachment.

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Description

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CROSS-REFERENCE TO RELATED APPLICATION

[0001]This application claims the benefit of U.S. Provisional Patent Application No. 61/033,559 filed Mar. 4, 2008 the disclosure of which is incorporated herein by reference.

BACKGROUND

[0002]Vehicle mounted tanks that carry liquids face design challenges not applicable to stationary tanks. The design challenges relate primarily to the mass and nature of liquid when put into motion. The vehicle carrying the tank may be hard to handle and may be prone to roll-overs due to the momentum of the liquid.

SUMMARY

[0003]In one exemplary embodiment, a liquid-holding tank for mounting on the frame of a vehicle is disclosed. The tank comprises an elongate tank body having curved side walls coupled to and disposed above a generally rectangular frame. The elongate tank body defines an interior chamber. The frame has generally vertical side walls extending from a generally planar tank floor. The generally vertical side walls are coupled to the curved side walls. The frame is adapted to directly support the tank on the vehicle frame, and the frame is further adapted to be in fluid communication with the chamber and receive the liquid, thereby lowering a vertical center of gravity of the tank. Front and rear vessel heads are coupled to the curved side walls and frame, and a lid is coupled to the curved side walls and the vessel heads. At least one longitudinal baffle is coupled longitudinally inside the chamber, and at least one transverse baffle is coupled transversely inside the chamber.

[0004]In another exemplary embodiment, a liquid-holding tank is disclosed comprising an elongate tank body having curved side walls coupled to front and rear heads. The tank body generally defines an upper liquid containment area and a closed-bottom tank frame is coupled to the curved side walls. The tank frame is further coupled to and extends between the front and rear heads. The tank frame extends downwards, and generally defines a lower liquid containment area which is fully open to the upper containment area. The upper and lower containment areas form a total containment area. The lower containment area is operable to lower a vertical center of gravity of the total containment area. The tank frame comprises an integral structural support and the tank frame directly contacts the vehicle frame. A baffle system is arranged to compartmentalize the total containment area and the baffle system comprises a plurality of longitudinal and transverse baffles. A top is coupled to the elongate body.

[0005]In yet another exemplary embodiment, a liquid-holding tank comprises an elongate tank body. A tank frame is coupled to the elongate tank body and extends downwardly therefrom. The tank frame and the elongate tank body form a reservoir and the tank frame is adapted to rest directly on the vehicle frame.

BRIEF DESCRIPTION OF THE DRAWINGS

[0006]Aspects of the present disclosure are best understood from the following detailed description when read with the accompanying figures. It is emphasized that, in accordance with the standard practice in the industry, various features are not drawn to scale. In fact, the dimensions of the various features may be arbitrarily increased or reduced for clarity of discussion.

[0007]FIG. 1 is a rear isometric view of the flooded-frame tank according to an exemplary embodiment.

[0008]FIG. 2 is a side view of the flooded-frame tank mounted on a truck chassis according to an exemplary embodiment.

[0009]FIG. 3 is a lateral cross-sectional view of the flooded-frame tank taken along line 3-3 in FIG. 2.

[0010]FIG. 4 is a longitudinal cross-sectional view of the flooded-frame tank taken along line 4-4 in FIG. 3.

[0011]FIG. 5 is a cut-away isometric view of a lower rear region of the flooded-frame tank according to an exemplary embodiment.

[0012]FIG. 6 is a top view of the flooded-frame tank according to an exemplary embodiment with a portions of the tank partially cut away.

[0013]FIG. 7 is a front isometric view of the flooded-frame tank according to an exemplary embodiment.

DETAILED DESCRIPTION

[0014]This disclosure describes a novel tank design for transporting a liquid. The novel tank design has a lower vertical center of gravity as compared to conventional tank designs. In particular, a typical horizontal tank designed for transporting a liquid cannot rest directly on a truck frame, but must have framing and legs to support the tank and to attach the tank to the vehicle. In such designs, the tank's vertical center of gravity is elevated and thus impacts the vehicle's handling and safety. Thus, the novel tank design, according to one embodiment includes a structurally sound tank frame that holds liquid and is open to the tank body, thereby flooding the tank frame and lowering the vertical center of gravity.

[0015]Referring to FIG. 1, a flooded-frame tank 100 is shown according to an exemplary embodiment in a rear isometric view. Tank 100 is generally constructed with an integral flooded frame 102 to which side walls 104 are coupled. A tank lid 106 connects side walls 104 together and functions to cover the top of tank 100, thereby forming an elongated body. Front and rear vessel heads 108 and 110 are coupled to flooded frame 102, side walls 104, and lid 106 to make tank 100 leak tight. These components of tank 100 may be welded or bolted, or otherwise fastened together in a suitable manner.

[0016]Referring now to FIG. 2, a side view of a flooded-frame tank 100, according to an exemplary embodiment, is shown mounted on a truck chassis frame 112. In this novel embodiment, flooded frame 102 rests directly on chassis frame 112. Flooded frame 102 may be bottom-supported directly by chassis frame 112 without any intervening support structure between chassis frame 112 and flooded frame 102. Since flooded frame 102 functions as a lower section of tank 100 and as a support structure of tank 100, conventional tank legs and structural support are no longer required. The removal of traditionally required tank legs and structural support is possible through usage of novel and non-obvious structural designs and construction methods which are disclosed herein. Thus, flooded frame 102 allows the center of gravity to be lowered. In some embodiments, the reduction or lowering of the center of gravity may be as much as five inches, or more.

[0017]Flooded frame 102 may be secured to chassis frame 112, for example, by a combination of side-attached mounts 114 and 116. Side-attached mounts 114 and 116 include spring-dampened mounts 114 and rigid mounts 116. Each mount 114 and 116, spans a distance from an outer vertical surface of flooded frame 102 to an outer vertical surface of chassis frame 112. Mounts 114 and 116 couple across corresponding outer vertical surfaces of flooded frame 102 and chassis frame 112 to substantially prevent sliding and separation between flooded frame 102 and chassis frame 112. Mounts 114 and 116 are preferably bolted to chassis frame 112 and welded to flooded frame 102, although either may be welded or bolted, or otherwise fastened in a suitable manner.

[0018]Rigid mount 116 is preferably used as the rearmost side-attached mount, and is paired with a corresponding rigid mount 116 which is similarly side-attached to an outer vertical surface of the opposite chassis frame rail (not shown). One or more pairs of spring-dampened mounts 114 are coupled at intervals along chassis frame 112. The quantity and exact positioning of mounts 114 and 116 may be determined based on the size of the tank, by usage requirements, and on other factors.

[0019]In other embodiments, straps may be used with or without mounts 114 and 116 to secure flooded frame 102 to chassis frame 112, by side-attachment to corresponding outer vertical surfaces. In yet other embodiments, flooded frame 102 and chassis frame 112 may be secured to one another according to any suitable fastening method, with or without side-attached mounts or straps.

[0020]A sill block 115, which is preferably a thin sheet of rubber, may be installed on chassis frame 112 before tank 100 is positioned to further isolate tank 100 from road vibrations, dampen tank movements, and minimize wear of flooded frame 102. Sill block 115 may be about one inch thick, though the thickness may be adjusted to achieve more or less vibration dampening. Other dampening devices are contemplated, such as, but not limited to, rubber or cork gaskets, wood shims, nylon pads, and the like.

[0021]Front vessel head 108 is preferably flat and rear vessel head 110 is preferably dished. In other embodiments either vessel head may be flat or dished. In addition, each vessel head is preferably flanged around its perimeter. The vessel head flange (not shown) fits inside an end of the elongated body to form an overlap which may be secured by welding, for example. In other embodiments, such as for a sanitary tank, the vessel heads may be secured by butt-welding, for example, to the elongated body.

[0022]FIG. 3 is a lateral cross-sectional view of flooded-frame tank 100 taken along section line 3-3 in FIG. 2. In cross-section, tank 100 may be described as having a modified square, or oval, configuration with radiused corners 105. Flooded frame 102 comprises a generally planar flooded-frame floor 118, which is shown in cross-section, with upwardly extending frame side walls 120. Frame side wall flanges 122 may project transversely from frame side walls 120 and extend along the longitudinal length of flooded frame 102 to provide for attachment to tank side walls 104.

[0023]The attachment of flooded frame 102 to side walls 104 may be further strengthened by pairs of boxed gussets 123, which may be included between flooded frame 102 and side walls 104 at the front and rear ends of tank 100, for example. Gussets 123 may be constructed by attaching a pad 125 to flooded frame 102 and tank side walls 104, followed by attachment of gusset 123. Gussets 123 are attached in pairs at front and rear ends of tank 100. Gussets 123 may also be attached to intermediate side wall locations which may or may not correspond with side wall locations supported by internal structures. Gussets 123 may also function as anti-roll stabilizers for tank 100.

[0024]Tank side walls 104 are continuously curved in this embodiment to distribute lateral forces exerted by fluid contained therein. This distribution of forces may prevent "oil canning" of side walls 104. In other embodiments the side walls may be substantially straight, or flat; or, the side walls may comprise a profile with curved and straight sections.

[0025]Tank lid 106 may attach to side walls 104 with bolts 124. In one embodiment tank lid 106 may be formed from a single piece of material, such as sheet metal, for example, and may include generally parallel upwardly projecting, generally vertical upper channels 126. In another embodiment tank lid 106 may comprise multiple pieces of material. In one embodiment upper channels 126 project upwardly about twelve inches, though other distances are contemplated. Upper channels 126 run longitudinally along both longitudinal sides of tank lid 106, and may be alternatively termed gussets or ribs. In one embodiment, upper channels 126 may form side walls for mounting external lighting and may establish a conduit space 127 for running wiring. In some embodiments upper channels 126 may be full-length, segmented gussets.

[0026]An end panel 130, may be coupled between upper channels 126 (as shown in FIG. 6), and conduit space 127 may be covered by a rear cap 129 (shown in FIG. 1). Upper channels 126 may also provide a degree of roll-over protection for various features such as a vent pipe 162 and a service access port 176 (both shown in FIG. 6). In addition, upper channels 126 may comprise sacrificial crumple zones which may absorb some of the force of a roll-over impact, thereby protecting other structural components.

[0027]Tank lid 106 may further comprise a flat portion 128, which functions primarily as a sealing cover for the top of tank 100. In some embodiments flat portion 128 functions also as a storage platform and may be coupled to, or maybe integral with, upper channels 126. In other embodiments, tank lid 106 may only comprise flat portion 128 without upper channels 126. Tank lid 106 may be entirely bolted onto tank 100 such that it may be entirely removed during construction, customization, maintenance and/or inspection. Tank lid removal allows tasks such as those listed to be accomplished under reduced or eliminated confined space requirements, potentially improving safety and reducing costs. In other embodiments tank lid 106 may be welded, or other wise permanently attached.

[0028]FIG. 4 is a cross-sectional view of the tank shown in FIG. 3 taken along section line 4-4. As shown in FIGS. 3 and 4, an interior space 132 of tank 100 may be variously divided by a baffle system 134 into smaller compartments, thereby reducing forceful liquid movements inside tank 100. Baffle system 134 comprises two main components, transverse and longitudinal baffles. An exemplary transverse baffle 136 is shown in FIG. 4, extending generally laterally across the cross-section of interior space 132. Transverse baffle 136 may be comprised of upper and lower ring sections 140 and 142, shown in FIG. 3, which are made integral by being welded together. Upper and lower ring sections 140 and 142 are then connected to an internal periphery of tank 100. Upper ring section 140 may comprise an upper flange 143, as shown in FIG. 4, for coupling to tank lid 106. Upper and lower ring sections 140 and 142 may be welded to the interior walls of tank 100 and bolted to tank lid 106, thus allowing transverse baffle plate 144 to be centrally bolted, or otherwise coupled, to the upper and lower ring sections 140 and 142. In some embodiments the transverse baffle plate 144 and upper and lower ring sections 140 and 142 overlap each other approximately 4 to 6 inches to allow for bolt-hole edge margins. In other embodiments, an integral ring section may be formed from more than two partial ring sections, or a monolithic baffle ring may be used.

[0029]At least some of the integral, structural tank support derives from the welding of an integral baffle ring to the interior walls of tank 100, including structural support for weight placed on tank lid 106. In other embodiments a significant amount of strength is derived from the integral baffle ring. During manufacturing, an internal ring may be comprised of four "quadrant" ring sections to reduce material waste, for example.

[0030]Transverse baffle 136 may comprise variations, perforations, holes or voids as shown in FIG. 3, including upper vent holes 146 for balancing pressure between divided compartments, transverse baffle service access ports 148 (see further function and description below), and fluid passages 150 for balancing fluid levels between divided compartments. As further shown in FIG. 4, three transverse baffles 136 are used to divide interior space 132 into lateral compartments. Other embodiments may include no transverse baffle, such as in a very small tank, for example, while still other embodiments may include one, two or more than three transverse baffles.

[0031]Turning now to a description of longitudinal baffles, as shown in FIG. 4, at least one longitudinal baffle 138 divides interior space 132 into left and right compartments, or longitudinal segments. Longitudinal baffle 138 comprises rigid longitudinal plates 156, 157 and 160 connected principally to transverse baffles 136 via various brackets 158. Forward and rear longitudinal plates 156 and 157 are bolted to the front and rear vessel heads 108 and 110, respectively. A vertical vent pipe 162 may also provide support for attachment of brackets 158 which support longitudinal plates 156 and 160. Brackets 158 may contain elongated slots 164, such that a longitudinal plate bolt hole may adjustably align over an elongated slot 164 permitting a bolt to be inserted transversely to couple the parts. Elongated slots 164 allow for easier fit-up during manufacturing and/or maintenance. Longitudinal plates 160 may be sized to increase ease of material handling during installation and repair as each longitudinal division between transverse baffles 136 may be comprised of multiple longitudinal plates 160. Longitudinal plates 160 may further be sized to increase material yield during manufacturing. For example, longitudinal plates 160 may be manufactured in quadrants to reduce scrap during manufacturing. In other embodiments, the longitudinal plates 160 may be monolithic, and may be welded or held in position by other suitable fastening means.

[0032]In addition to having the assembly and material usage advantages described above, the novel assembly of baffle system 134 may provide a benefit against corrosion, especially microbial induced corrosion. Material properties in areas near a weld, which are typically larger than the weld itself, may be negatively affected by the welding process. For example, a heat affected zone created by welding stainless steel may significantly reduce corrosion resistance, especially along the edges of the weld. Thus, by using mechanical fasteners, such as threaded fasteners, for example, baffle system 134 may be more resistant to corrosion at attachment interfaces. In some embodiments, a laminating protection may be applied to the tank interior surfaces and components.

[0033]FIG. 5, is a cut-away isometric view of an exemplary lower rear region of tank 100. Since structural tank support is integral to tank 100, no external supports are required for attachment of flooded frame 102 to chassis frame 112 (shown in FIG. 2). At least some of the integral, structural tank support derives from the coupling of a strap 152 to a lower edge of transverse baffle 136. Strap 152 may be formed to match a lower edge profile of transverse baffle 136. Strap 152 may then be welded to the lower edge of transverse baffle 136, thereby create a lower baffle flange 154. Lower baffle flange 154 may be T-shaped in cross-section, and may be welded to flooded frame 102. Strap 152 and transverse baffle 136 may be welded together, as mentioned, or a lower baffle flange 154 may be created by another process such as machining a flanged ring from a solid block, casting, and the like. Strap 152 and transverse baffle 136 may be similarly combined with or without additional components to provide other structurally significant cross-sections, such as an L-shape, a J-shape, and the like. In embodiments where transverse baffle 136 comprises a transverse baffle plate 144 and a lower ring section 142, a lower baffle flange 154 may be constructed by welding a strap 152 to a lower edge of lower ring section 142. Strap 152 may also function as a doubler, or backup pad, to distribute the force of the lower edge of transverse baffle 136, or the force of the lower edge of ring section 142.

[0034]Referring again to FIG. 4, a full-through venting system 166 is provided to reduce or eliminate vacuum that may be created by draining liquid. FIG. 4 shows vertical vent pipe 162 located near front vessel head 108. Vent pipe 162 extends upwards through a penetration in tank lid 106 and downwards to a flange 168 near flooded-frame floor 118. The extension distance of vent pipe 162 above tank lid 106 is preferably about three inches. The extension distance may also be more or less than three inches. If the extension distance is more than three inches, it should still be less than the vertical projection of upper channels 126. A longitudinally oriented, closed vent trough 170 is coupled to flange 168. Vent trough 170 generally extends between flange 168 and flooded-frame floor 118, and may extend rearward along flooded-frame floor 118 past the last vehicle axle. Vent trough 170 is sealed to flange 168 of vent pipe 162 and closed all the way around. Vent trough 170 is open to the atmosphere underneath tank 100 via a hole 171 in flooded-frame floor 118. FIG. 5 shows hole 171 through a cut away in vent trough 170. Hole 171 preferably has a diameter of about six to about eight inches, although other shapes and dimensions are contemplated.

[0035]Referring now to FIG. 6, a top view of tank 100 is shown according to an exemplary embodiment with portions of the tank partially cut away. Towards the front end of tank 100 a service access port 176 is included which is open to interior space 132. Service access port 176 is covered by a removable grating 177 which may have about one inch spacing. An overflow basin 173 surrounds both service access port 176 and grating 177. Overflow basin 173 may be covered by a basin lid 175 which may be hinged and latched. Basin 173 may be comprised of an entirely separate enclosure or may be comprised of components such as upper channel 126, end panel 130 and a lateral divider 184. Lateral divider 184 may be coupled between upper channels 126 similar to end panel 130. In addition, basin 173 may be about 24 inches wide and about 30 inches long. Turning briefly to FIG. 7, an alternative embodiment is shown with basin 173 comprised of upper channel 126, end panel 130, a lateral basin wall 186, and a longitudinal basin wall 188. In other embodiments basin lid 175 is not required. In another embodiment, grating 177 comprises a vented basket that drops a few inches into tank 100.

[0036]During draining, as fluid volume rapidly decreases inside tank 100, air from outside tank 100 is sucked into venting system 166 to fill the fluid-evacuated volume, thereby allowing fluid to drain without creating a potentially damaging vacuum inside tank 100 that may restrict fluid draining and adversely impact the structure of tank 100. Venting air enters through hole 171, travels through vent trough 170 and vent pipe 162, and enters the tank through grating 177, such that tank 100 is constantly vented. In other embodiments, vent pipe 162 and service access port 176 may be together located at alternate positions such as near the middle or towards the rear of tank 100. The positioning of vent pipe 162 and service access port 176 near the front of the tank may function to reduce liquid spillage due to closer placement to a mid-point of the vehicle wheel base. Flexibility of positioning vent pipe 162 and service access port 176 may be enhanced by locating and extending vent trough 170 along the bottom of tank 100. However, in other embodiments, a vent trough may be located above the bottom of tank 100 or positioned left or right of a longitudinal midline.

[0037]During filling of tank 100, an overfill condition may arise when fluid rises above grating 177 and fills basin 173. Excess fluid is able to exit basin 173 by entering vent pipe 162, traveling along vent trough 170, and exiting through hole 171. Fluid may be prevented from shooting upwards by basin lid 175. During abrupt stops, fluid may slosh forward and partially fill basin 173. If the fluid rises above vent pipe 162, then the fluid is directed to safely exit through hole 171 behind the last wheels. Removable grating 177 may also provide quick access for liquid filling and removal.

[0038]As described above, and as shown in FIG. 5, liquid may drain, or dump, from flooded frame 102 to transverse drain trough 172, which opens on either side of tank 100. The liquid may also drain through a dump valve flange 174 which opens to the rear of tank 100. In some embodiments, tank 100 may have a drain comprised of a single dump valve opening, which may be either side- or rear-exiting. Venting air may also enter through the dump valves 172 and 174 during draining. In another embodiment rearmost gusset 123 has a reduced width because a part of its function is accomplished with transverse drain trough 172.

[0039]Service access, in addition to that mentioned briefly above with respect to removable tank lid 106, is now described referring to FIG. 6. Basin lid 175 is lifted and grating 177 removed to access service access port 176, which provides access to at least one compartment inside tank 100. From this first compartment, service access to other compartments is obtained through transverse baffle service access ports 148 (shown in FIG. 3) formed in transverse baffle plates 144, and in another embodiment, by one or more hinged longitudinal baffle service access panels (not shown).

[0040]Referring to FIG. 3, transverse baffle service access port 148 may be provided by cutting or punching a circular, scalloped-shaped opening, which may be a shape such as a circle ringed by an array of radially extending rectangles or tabs. The punched or cut-out scalloped-shaped coupon may then be rotated and coupled over service access port 148 as an access cover 178. Voids 180 left in the transverse baffle plate 144 by the removal of radially extending rectangles or tabs may be sized to permit fluid controlled flow between lateral compartments. Voids 180 may also be sized to enable a service person to pass a hand or arm though to aid in the removal or fastening of mechanical fasteners holding access cover 178 in place. Pairs of transverse baffle service access ports 148 may be provided in each transverse baffle 136. In other embodiments, transverse baffle service access ports 148 may have different shapes such as oblong and square, among others, and access cover 178 may have one or more radially projecting tabs.

[0041]Referring to FIG. 7, a front isometric view of flooded-frame tank 100 is shown according to an exemplary embodiment. Tank lid 106 is shown in a storage configuration with upper channels 126 spaced approximately four feet apart to form side walls for a storage area 182. Storage area 182 may be further defined by lateral divider 184 and a longitudinal divider 185. In addition, when not functioning as part of basin 173, dividers 184 and 185 may be adjustable to make storage area 182 user-configurable. Storage area 182 may include a cargo tie down system (not shown). As configured in FIG. 7, storage area 182 may be used to store implements and supplies. For example, a fire hose (not shown) may be stored in a vertical or horizontal accordion pattern on tank lid 106 between either upper channel 126 and longitudinal divider 185.

[0042]As shown in FIG. 7, head channels 202 are secured at an angle to front vessel head 108. In cross-section, each channel 202 may be a hat-channel, though other cross-section are contemplated. An upper end of channel 202 overlaps a front cap 198 which covers conduit space 127 by coupling to the front end of upper channel 126. Front cap 198 has a lower opening, created from formation of a tab 204. Tab 204 covers the channel opening at the upper end of channel 202, thereby establishing a protected path between conduit space 127 and channel 202. A lower end of channel 202 is open. In other embodiments, the front vessel head may be dished and may comprise channels 202 that have been contoured to approximate the dished curve of the head.

[0043]Channels 202 may function to strengthen front vessel head 108, especially against oil-canning. In addition, channels 202 may function to protect, conceal, and guide wires between the conduit space 127 and the underside of the tank by allowing wires to travel through conduit space 127, out through the lower opening in front cap 198, into channel 202, and down to the bottom of the tank. Electrical wiring in conduit space 127 may be accessed by removing front or rear caps 129 and 198, or by removing an outer wall of upper channel 126. In other embodiments, channels 202 may support control panels, accessories, or auxiliary systems.

[0044]Optional outriggers 190 may extend laterally from flooded frame 102 and provide further equipment attachment points, such as for tool boxes and the like. Outriggers 190 may be constructed by attaching a pad 192 to flooded frame 102, followed by attachment of an outrigger beam 194 and an angled support bracket 196 to pad 192.

[0045]Other additional embodiments and alternatives are contemplated for various features of tank 100. According to one embodiment, an internal width of tank 100 is about 77 inches with an internal height of about 59 inches. Other dimensions for internal and external sizing are contemplated to meet payload requirements or access restrictions. Tank 100 can be constructed of various materials including steel, stainless steel, aluminum, plastics, fiberglass and composites.

[0046]Although embodiments of the present disclosure have been described in detail, those skilled in the art should understand that they may make various changes, substitutions and alterations herein without departing from the spirit and scope of the present disclosure. Accordingly, all such changes, substitutions and alterations are intended to be included within the scope of the present disclosure as defined in the following claims. In the claims, means-plus-function clauses are intended to cover the structures described herein as performing the recited function and not only structural equivalents, but also equivalent structures.

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